List of formulas in elementary geometry

This is a short list of some common mathematical shapes and figures and the formulas that describe them.

Two-dimensional shapes

Shape	Area	Perimeter/Circumference
Square	A = side^2	P = 4 x side
Rectangle ( l = length, w = width)	A = l × w	P = 2l + 2w
Circle	A = π × $r^2$	C = 2 × π × r
Ellipse (where a is the semimajor axis and b is the semiminor axis)	A = π × a × b
Triangle (b = base, h = height, a,b,c = sides)	A = ½ × b × h	P = a + b + c
Parallelogram (b = base, h = height, a = side)	A = b × h	P = 2a + 2b
Trapezoid (where a and b are the bases)	A = ½(a + b) × h

Sources:^[1][2]

Three-dimensional shapes

Shape	Volume	Surface area
Cube	$V=s^3$	$6s^2$
Rectangular Prism l = length, h = height, w = width	V = l × w × h	S = 2lw + 2lh + 2wh
Sphere	V = ($4/3$) π $r^3$	4π $r^2$
Right Circular Cylinder	V = π × $r^2$ × h	S = 2π rh + 2π $r^2$

Sources:^[3]

LaTeX markup (for writer/editors)

Circle (area and circumference)

$C = \,2\pi r$

$A = \,\pi r^2$

$dA = \,\mathrm{d}r\,r\,\mathrm{d}\theta$

Sphere (area and volume)

$A = 4\pi r^2$

$V = \frac{4}{3}\pi r^3$

$dA = r^2 \sin\theta\, d\theta\, d\phi$

$\mathrm{d}V=r^2\sin\theta\,\mathrm{d}r\,\mathrm{d}\theta\,\mathrm{d}\varphi$

References

1. http://www.austincc.edu/tutor/students/resources/Geometry.pdf
2. http://www.math.com/tables/geometry/areas.htm
3. http://www.math.com/tables/geometry/volumes.htm